Computer Beeping continuously

Hello... I just got my motherboard and ram changed 2 months ago in my windows 7 pc because it was not booting up... Then around 7 days ago it showed up a blue screen ( i did not get time to read what was written on it because it shut down within a second ) and shut down immediately... When i tried to boot it up... It started to beep continuously ( did not boot up that full day)... It booted the next day smoothly and was workin till today... While i was workin on some stuff... It's pixels broke up showin some kinda black and little colorfull lines... With a very irritating sound... You know... Not booting up again and beeping up continuously... What could be the reasons and the cure???